Radiation fields in moving media: new analytical and numerical solutions of the transfer equation

Significant progress has recently been achieved in the solution of the radi ative transfer equation for various geometries, velocities, scattering mode s etc. In particular, it has been become possible for the first time to der ive an orthogonal system of functions that solves the transfer equation for plane media, to model numerically radiation fields in arbitrarily shaped 3 D configurations with a prescribed accuracy, and to obtain general quadratu re solutions for spheres with relativistic velocities. The latter are of sp ecial importance since they lead to accurate and convenient expressions for the diffusion limit in moving media. In this contribution the new techniqu es are reviewed and the consequences for our understanding of radiation fie lds briefly discussed. (C) 1999 Elsevier Science B.V. All rights reserved.